That’s fully consistent with the idea that there has to be some threshold for lead in food because it’s literally naturally occurring in the soil.
In fact, to fully avoid lead, you’d basically have to carefully grow food hydroponically. Certified Organic mineral fertilizers like basalt rock dust (which provide calcium, phosphorus, and potassium, etc) would obviously not be okay if you wanted to eliminate all lead, as basalt contains 7.5ppm lead, comparable to the average in the Earth’s crust.
